Graphene oxide（GO）can realize film-forming covering and plugging of nano-micro pores in shale. In order to improve its temperature resistance，carboxylated graphene oxide（GO-COOH）was prepared by an improved carboxylation reaction，its structure was characterized and its performance of reducing pore pressure transmission and its compatibility with the drilling fluid was evaluated. The carboxylated graphene oxide was applied in the mud shale interval of Funing Formation in Yancheng area， Jiangsu. Infrared and XRD results showed that the method used in this article had successfully introduced carboxyl groups onto the graphene oxide sheet；after keeping the sample at 180 ℃ for 16 hours，the pressure transmission time of GO-COOH was 2120 s， while that of GO was only 820 s，which indicated that GO-COOH had a strong plugging ability at the high temperature. After GO-COOH was added to the polyamine drilling fluid system，it had little influence on the rheological properties of the system，and could improve its inhibition and fluid loss performance，and reduced the depth of sand bed invasion. The pressure transmission of the polyamine system was reduced from 1 MPa to less than 0.1 MPa in 50 hours with GO-COOH added，indicating that GO-COOH had good compatibility and plugging performance. The average hole diameter enlargement rate of field test wells was only 8.33%， the average accident time was only 1.03 d，and the drilling duration was 48.33 d. Compared with the pre-construction，the hole diameter enlargement rate was greatly reduced，and the downhole accident complex time was greatly reduced，and the drilling duration significantly reduced. The addition of GO-COOH had effectively alleviated the problem of borehole wall instability of the Funing Formation and produced good economic benefits.